By the method of fuzzy clustering, the temporal dynamics of the arthropod community and sub-communities in two different management areas in organic pear orchards were studied in Shunyi, Beijing. The results showed that Psyllidaes were the predominant insects in sparsely- and densely-planted areas, and their relative abundances were 0.3801 and 03300, respectively. The total community could be grouped into 5 clusters (D=1.87) in planted areas and 3 clusters (D=1.80) in densely-planted areas. The pest sub-communities could be grouped into 3 clusters (D=1.80) in sparsely-planted areas and 4 clusters (D=1.80) in densely-planted areas. The natural enemy sub-communities could be grouped into 4clusters (D=2.12) in sparsely-planted areas and 5 clusters (D=1.75) in densely-planted areas. The number of Psyllidaes was very large in the densely-planted areas in early spring and in sparsely-planted areas in autumn. It is therefore suggested that investigation during these periods be ntensified and prevention implemented.